The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 30, 1996
Filed:
Apr. 06, 1995
Tim Danielson, Monument, CO (US);
Kaman Instrumentation Corporation, Colorado Spring, CO (US);
Abstract
This invention uses a single eddy current coil to measure multiple parameters of conductive target simultaneously using a single fixed frequency. For example, the system consisting of the sensor coil, connecting cable, and signal conditioning electronics, can measure the thickness of a target and the distance of the target from the coil. Alternatively, it could simultaneously measure the distance of the target to the coil, i.e. lift-off, and one of the electrical properties of the target, such as the resistivity. The present system is useful in material characterization of targets where the lift-off information can be used to correct for any lift-off induced error in the apparent resistivity. In general, it can determine any pair of two characteristics of the target/sensor relationship simultaneously. This invention provides significant improvement in accuracy and flexibility of eddy current sensors and can be manufactured at a low cost due to the use of a single coil and a single fixed frequency in the signal conditioning electronics. An alternative sensor configuration utilizing two sensors differentially to produce a cladding insensitive--displacement measurement is also contemplated by the present invention.